Machine for cutting sheet metal



Jan. 10, 1950 A. l. K. SLETTENGREN 2,494,413

MACHINE FOR CUTTING SHEET METAL Filed Jan. 27, 1947 3 Sheets-Sheet l A. l. K. SLETTENGREN MACHIFNE-FOR CUTTING SHEET METAL Jan. 10, 1950 3 Sheets-Sheet 2 Filed Jan. 27, 194'? In U ezaiop 1.,1. If ,Jlei'ie J n. 10, 1950 A. x. K. SLETTENGREN MACHINE FOR CUTTING SHEET METAL 3 Sheets-Sheet 5 Filed Jan. 27, 1947 wgg Ila/v ezzrt Patented Jan. 10, 1950 Anders ll-ngemar Knutsson SlettengremGoteborg; Sweden, assignor' to Verkstads-A. B. Haldex,

Halmstad, Sweden ApplicationJanuary 27, 1947-, SerialNo: 724 ,49-7 In. Sweden February 6, 1946 The: inventionrefers to such machines for the cutting. of sheet-metal or similar materials, wherein the cutting toolis actuated by a togglejoint provided with twolinks, which are pivoted,

- the one about a fixed pin and the other about a pin onthe tool holder, said links being adapted to have an oscillatory transverse movement imparted thereto in a plane extending at right angles to their axes of oscillation, which movement is produced by means of a connecting rod or the like actuating: the. intermediate link pin of the toggle-joint. In known machines of this.

type, the fixed point of the-toggle-J'oint is adaptedv to be shifted in two extreme positions, i. e. one. working position, whereinlth'e. tool holder moves. sov that the edges of. the cutting tools are operating relatively near to one; another, and an idle position, wherein. the edges of: the cutting toolsare operating at. a greater distance from each other, so that the work piece can be freely introduced between the edges: of the. tools. Said shifting. is preferably efl'ected. by an adjustment ofthe fixed pin ofthe link system, which pin..

is eccentrically mounted, whereby the: fixed link pinmay be caused. to take up anupper anda.

lower position- In the cutting; of sheet-metal of varying thicknesses and different materials, it will be founddesirable to control the length of stroke-of the movable tool and the number of. strokes thereof In. a toggle-joint of. the:

within certain limits. type in consideration,. such control may be provided by varying the magnitudezof-z the oscillatorytransverse movements of the links toward both sides from the plane extending. through the two outer link pins. Preferably, the movement is then adjusted so that the links are caused to swing symmetrically on both sides. of said plane, in the one case, and substantially on one side of said plane in the other case. The transverse movement attacking the intermediate pin of the links is assumed; to proceed with a constant amplitude and frequency. In the first case, a resulting movement of the tool is obtained, which is distihguished by a small stroke at a. certain oscillatory frequency, whereas in theother case a greater stroke of the tool is obtained at a frequency half as great as that in the former case. In the machines as previously known, said conditions of motion have been obtained by the fact that the intermediate link pin of the links would be actuated by a connecting rod, the other end of which would have a rotary movement imparted thereto from an eccentric rotating about a rigid shaft, and the length of which would be varied 3 Claims. (01. 74-38) in any suitable manner The same effectmay also toggle-joint.

be. obtained by setting the. axis of rotation of the eccentric to varying. distances: from theplane extending through the outer link pins ofthe In both of these. cases,v separate means mustv be provided to render possible the shifting ofthe length. of. stroke of the cutting, tool and the shifting of. the fixed point of thetoggle-jointv into its upper and lower positions. y; respectively.

The present invention relates. to. a. simplified:

means for the shifting; of the. length of stroke, and is principally distinguished.- by the fact. that. the fixed link pin is fixedly adjustable: into. vari- 'ous positions. displaced transversally ofthe. di rection of movement. of the tool holder, in a manner such that the.- plane; extending; through the twozouter link pins may beradiusted to dinerent distances. from the: extreme positions of the intermediate link pin..

The invention will. be described more closely with reference tothe. accompanying drawings.

Figs. 1 and 2 illustrate diagrammatically twodifierent working positions. of the adjustable link point.

Fig. 3. shows a toggle-joint in; longitudinal section. v

Fig. i is a sectional. sideelevation on line :l--4 of- Fig. 3.

Rotatably arranged about the stationary shaft.

transversely l of the driving motor. is. an eccentric with the centre point 2 and theradiusR. From here the motion is transmitted over the connecting rod L to the intermediate link point: of the togglejoint, saidlink. point having its extreme posii-t tions- 3, 4- at the distance of. 2R from each other. The upper fixed. link. point. is designated by 5;, and 6 denotes the lower, vertically guided link point in its lowermost position, whereas I designates this latter link point in its uppermost, position. The points, 6 and constitute the end points of. the movement of the cutting tool in. its. working position. According. to Fig. 1, the: intermediate point of the toggle-joint moves to: varying. distances from the plane extending As a result, a relativel'y long working. stroke 6--'| and a very small.

through the points 5 and. 6.

additional stroke 6-9 of the tool holder are obtained. The. fixed link point 5 is eccentrically mounted, and may thus be moved to the point 8 by a turning movement of the corresponding journal, so as to cause the whole toggle-joint to be raised, so that the tool holder will move at a greater distance from the corresponding stationary cutting tool (not shown). The tool then operates in an idle position, and work pieces may be introduced between the cutting tools.

Fig. 2 shows the fixed link point as shifted into a position 5', which has been attained by a continued turning movement of the eccentrically positioned journal. The position is preferably adapted so that the distancebetween the extreme position 6 of the movable outer link point and the alternative positions 5 and 5 of the stationary link point is the same in both cases. At the same time, the fixed link point will be displaced laterally with respect to the other unchanged parts of the system, whereby the plane between the outer points 5' and 5 of the toggle-joint may be set into a symmetrical position relatively to the extreme positions 3' and 4 of the oscillating link point, which latter positions are fixed relatively to the plane extending through 5 and 6. Hereby a shorter working stroke of the tool holder is obtained, which is how caused to move between the points 6 and 1' at a stroke frequency which is doubled as compared with the conditions in Fig. l.

The toggle-joint consists in one upper link 20 journaled on an upper link pin It over a bushing 21 and one lower link 22 pivotally connected to a tool-holder 23 by means of a link pin 24. The links 28 and 22 are connected to each other by an intermediate link pin 25, the lower link 22 being journaled on the pins 24 and 25 by bearings 26 and 27, respectively. At the lower end of the tool-holder 23 there is a shear tool 28 mounted by any common attaching means 29.

Oscillating movement is imparted to the intermediate link pin 25 by an eccentric mounted on a stationary driving shaft 3| and generally referred to by the reference numeral 30. The eccentric has its center of rotation in point i eccentrically positioned relative to the center 2 of an eccentric disc 32 in an eccentric strap 33 and provided with a ball-bearing 34. The eccentric strap 33 is connected to the intermediate link pin 25 by an eccentric rod 36 which is forked at the link end to form lugs 31 engaging the pin 25 over bushings 38.

' The upper link pin I is rotatably mounted in the opposite walls 4| and 42 of the mechanism casing 49 by an aligned rear shaft end H and a front shaft head 12 of the pin shaft H] which is eccentrically arranged relative to its journals H and I2. At the outer end of the shaft head I2, there is a handle I! pivoted about a pin I8 against the compression force of a spring l9 anchored in the head l2. By means of the handle 11, the link pin H] can be: rotated and fixed in any one of three positions 5 and 8 by snappingin the handle I! into one of the recesses l4, I5 and i6, in the casing wall 42.

The position occupied by the handle IT, as shown in Fig. 4, corresponds to the position 5' indicated in Fig. 2, providing for the tool-holder 23 two equally large strokes per revolution of the driving shaft 3|. By simply shifting the handle 11 to recess l5, the single stroke operation of Fig. 1 will be obtained. If, however, the handle I! be swung to recess l6 corresponding to position 8 of Figs. 1 and 2, the tool-holder 23 will be lifted out of operating position and the tool will not cut but permit a work-piece to be inserted or removed, as the case may be.

The advantage of the invention primarily resides in that the raising of the cutting tool and the shifting of the stroke thereof may be effected by means of the same operating lever. Moreover, the invention highly simplifies the shifting of the length of stroke as such shifting may be eifected by a single manipulation even during the operation of the machine. The invention also provides for a simple and condensed assembly of the shifting mechanism within a closed housing.

What I claim is:

1. In a machine for cutting sheet-metal and similar materials a toggle-joint arrangement comprising in operation two links, one stationary link pin, one intermediate link pin and one movable link pin, said movable link pin being connected to a tool holder arranged to reciprocate rectilinearly, driving means connected to said intermediate link pin to oscillate the same between extreme positions transversely of the direction oi movement of said tool holder, one of the links being pivoted about said stationary and said intermediate link pins and the other link being pivoted about said intermediate and said movable link pins, said stationary link pin being movable into at least two positions transversely displaced relative to the direction of movement of the tool holder, and both of said positions being at a distance from a given common remote extreme position of said movable link pin equal to the maximum distance between the stationary and movable link pins, the plane extending through the axes of said stationary link pin when located in at least one of said positions and of said movable link pin passing between said extreme positions of the intermediate link pin, and locking means for fixing said stationary link pin in either of said transversely displaced positions.

2. Arrangement as claimed in claim 1, characterized in a shifting device, said stationary link pin being secured to said shifting device, and

' said shifting device being capable of moving said stationary link pin into said at least two positions and into a position longitudinally further apart from said common extreme position of" said movable link pin than said two positions,

the said locking means fixing said stationary link pin in either of all said positions.

3. Arrangement as claimed in claim 2, in which said shifting device is an eccentric.

ANDERS INGEMAR KNUTSSON SLETTENGBEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Klocke Apr. 21, 1942 

